CVR 19 Flashcards
Describe the structure of the artery?
Tuna intima which is the innermost layer.
Tuna media which is mainly smooth muscle and is the part that is contractile.
Tuna adventitia which is mostly connective tissue.
What is the significance of arterioles?
After arteries, form the arterioles which have sphincters that act as control valves.
Bloodflow is regulated via the _____ which is a form of autoregulation called the ____ and uses reactive and active hyperaemia.
Intrinsic local control
Myogenic hpothesis
In the extrinsic regulation of peripheral blood flow the ____ receptor of the ___ NS causes vasocontricion. However in the _____ pathway ___ causes NO dependent vasodilation?
alpha receptor of the sympathetic.
Parasympathetic Ach
What is the average rate that the wave in an arterial pulse can be felt?
7m/sec
Arterial blood pressure is _____ in type and has a peak pressure during ____. which in a healthy young adult averages ____ in systemic and ___ in pulmonary.
pulsatile
Systolic
120
25
How do you find the mean systemic arterial pressure?
diastolic + 1/3 pulse pressure
What are the main determinants of systolic and diastolic pressure?
Systolic - CO - preload (venous return) heart rate, contracility, afterload.
Diastolic - resistance to flow
The most immediate important control mechanism in controlling BP over time is the ____ because it determines both ____ and ____.
Over a long period however is ____ and ____ homeostasis.
baroreceptor reflex
CO and PR
renal regulation
sodium and water
Where are the baroreceptor?
Adventitia of large vessels and media of smaller ones. Afferents discharge when BP and pule increase.
Baroreceptor nerve terminals in the walls of the ____ sinus and the ____ arch respond to vascular stretch from BP. Increased frequency is enhanced by ____ in BP.
carotid
aortic.
increase
Nerves ____ and ____ integrate in the medulla. Stimulation of the NTS inhibits ____ outflow to the peripheral BVs.
Lesions of the NTS produce _____.
9 and 10
sympathetic
vasoconstriction
Ultimately what wil decrease in MAP do to SNS and PNS?
SNS - increase
PNS - decrease
Baroreflex triggers occur from a _____ in venous return?
decrease
What affect does decreasing systemic BP cause baroreceptors to have on systolic and diastolic?
Systolic - increase
Diastolic increased
Whereas incraesing causes decreased systolic and decreased diastolic